I've seen trouble with all engines. I've sent many back to Hobbico...and this is for the store not my personal stuff.

From my findings, Odonnell Speed Blend has torched a good bit of engines. I believe the window is a little more narrow with it.

A combo I enjoy is Nova with Byrons. I don't know the last time I changed the glow plug. The Nova's just love Byrons fuel. Simply the best tuned engine you will get.